The present applicant has already proposed an operation button equipped with a flow rate adjusting function capable of coping with a change in pressure of contents spraying gas as described later in references 1 and 2.
The flow rate regulator adjusting mechanism in the operation button substantially comprises the following basic components:
(21) a body (chassis) of an operation button;
(22) a cylinder mounted on the body and including a recessed part changed in the longitudinal depth to adjust the size (cross sectional area for contents passage) of a passage space region of contents flowing in from a stein and similarly including a hole part for adjustment;
(23) a sheath-shaped piston member disposed in the cylinder, which is movable longitudinally with respect to the recessed part and the hole part;
(24) a coil spring settled between the piston member and the body for energizing the piston member forwardly;
(25) an discharge piece for contents passing through the passage space region or the like.
The flow rate adjusting piston member changes an inflow cross-sectional area of the passage space region of a contents by permitting itself to move longitudinally, based on the magnitude relation between elastic force of the coil spring and spraying gas pressure received by itself.
The piston member receives backward force as a whole by the spraying gas pressure of the inflow contents, and if the backward gas pressure becomes stronger than forward energizing force of the coil spring, then the piston member moves backward.
As the piston member moves backward, the contents inflow cross-sectional area of the passage space region is reduced correspondingly to decrease an amount of the inflow contents into the piston member. In other words, backward gas pressure to the piston member is weakened.
This causes the energizing force of the coil to surpass the gas pressure and so the piston member to move forward.
The forward movement of the piston member permits the contents inflow cross-sectional area of the passage space region to again become large and permits the enough contents to flow into the piston member. Thus, the piston member moves backward with pressing force based on the spraying gas as in the time the operation was started.
In the actuation mode where the operation button is pushed, the longitudinal movement of the piston member is repeated.
In the actuation mode, as described above, in accordance with a change in the pressure of the contents spraying gas,
(31) in case of the spraying gas pressure being strong, the piston member is shortened in its time required for its movement from its front position to its rear position (substantially equal to the time interval when the contents flow anew into an internal space part of the piston member),
(32) in case of the spraying gas pressure being weak, the piston member is lengthened in the time required for its movement.
More specifically, when the spraying gas pressure is weak, the total inflow cross sectional area obtained by integrating actual inflow cross-sectional areas of the passage space region at respective time points with time is set to be large.
When the contents spraying gas pressure in the container body is high (8 Kg/cm2) as in the initial stage of the use,
(41) the piston member receives large backward force based on the associated gas pressure and
(42) a backward moving speed of the piston member is high, so that a time portion in which the contents inflow through large cross sectional area of the passage space region, becomes small.
In contrast, when the contents spraying gas pressure in the container body becomes low in accordance with the use of the aerosol type product, e.g. 3 Kg/cm2, compared with the case of the high gas pressure,
(51) the piston member has less backward force caused by the associated gas pressure,
(52) the piston member becomes slow in its backward motion, so that a time portion in which the contents inflow through large cross sectional area of the passage space region, is increased.
It is noted that the forward moving speed of the piston member by the coil spring is substantially not changed whatever the strength of the contents spraying gas pressure is.
Consequently, the contents inflow cross sectional area per unit time in the passage space region is automatically adjusted by a change in the contents spraying gas pressure in the container body so that it is possible to stabilize the amount of discharge of contents in aerosol products.
Reference 1: Japanese Unexamined Patent Application Publication No. 2004-136212
Reference 2: Japanese Unexamined Patent Application Publication No. 2004-313841